Dissimilarities in volume and function of social brain regions in autism.

Despite growing awareness, diagnosing Autism Spectrum Condition (ASC) in adulthood remains challenging due to a limited range of diagnostic tools beyond psychological assessments. Although recent neuroimaging advancements have identified social brain regions (SBR) associated with sociability, research on these areas in ASC, particularly within the largely understudied adult ASC population, remains scarce. Explore functional and volumetric differences in the SBR between autistic and neurotypical individuals. We conducted a volumetric and functional assessment of SBRs using open-source MRI data from the Autism Brain Imaging Data Exchange (ABIDE). The sample included 44 adult ASC (37 male, mean age 25.86 ± 6.58) and 64 adult neurotypical individuals (51 male, mean age 25.36 ± 4.05). Autistic adult individuals demonstrated lower left nucleus accumbens volume. The amplitude of low frequency fluctuations was enhanced in the orbitofrontal cortex and temporoparietal junction, and decreased in the caudate, hippocampus, thalamus, and ventral tegmental area in the autistic group. Additionally, a widespread increase in functional connectivity within the SBR was demonstrated in the ASC group. Structural and functional measures allowed classification of autistic and neurotypical individuals with 76% accuracy using a support vector machine model. The results demonstrate significant SBR differences between adult autistic and neurotypical individuals, highlighting the SBR as potentially essential in ASC etiology, we demonstrate its ability to classify autistic and neurotypical individuals. However, further exploration of the SBR using advanced imaging techniques is required.